There's a moment late in the documentary Talihina Sky: The Story of the Kings of Leon (premiering on Showtime August 21st) where Nathan Followill, operating the video camera, confronts his visibly inebriated brother Caleb, and begins laying into him loudly and mercilessly. "You don't realize – you get drunk and you talk shit to everybody who makes you who you are," Nathan yells. "You're a piece of shit and your band cannot fucking stand you!" Caleb hangs his head shamefully, but Nathan's tirade continues. "I sing every goddamn song for you because your little pussy-ass voice gets hoarse! Fuck you – we have made you."

That Mitchell chose to include it at all is a good indication of the level of candor present throughout the film, which traces the brothers' ascent from the harmony-singing scion of a devout Pentecostal family (there's an early clip of Caleb and Nathan performing "When We All Get to Heaven" on public access television as teenagers) to packing arenas around the world. It also unflinchingly explores a religious past that still weighs heavily on them, manifesting itself in unexpected – and often unsettling – ways. As Caleb puts it, "As soon as I knew we were about to get a record deal, I never slept. I knew I was going to hell. And I couldn't live with it."

Culled from over 700 hours of footage, Talihina Sky volleys between clips of the group recording and performing – as in the clip above, which offers a glimpse at a particularly fraught moment during the recording of "Only By the Night" – to footage taken at the Followill clan's rowdy annual family reunion. In fact, their extended family is almost as important to the film as the group itself. Rowdy and bawdy, they're clearly proud of their famous namesakes, but they also keep them grounded, reminding them of their roots. "They’re very colorful and special characters," Mitchell says. "I’d always been told about these people by the boys, and so when I finally got to meet them, they welcomed me in and sort of treat me like a family member, too. They hold [the band] very close, and keep their lives real."

Arguably none moreso than the group's "Uncle Cleo," who opines on everything from horseshoes to grass snakes and, as the film progresses, comes to serve as the embodiment of their Southern roots. " If you wanna keep it real, Uncle Cleo will help you keep it real," Mitchell chuckles. Though Cleo passed away before he got to see the film, his presence acts as a kind of balancing after long shots of screaming crowds and hotel room debauchery. Talihina Sky also offers a rare on-camera interview with Caleb and Nathan's father Ivan, a onetime Pentecostal preacher clearly conflicted over the path Caleb and Nathan have chosen. (There's a point in the film where Mitchell asks Ivan if he thinks his sons are doing with their lives what God would want, to which Ivan, clearly distraught, answers, "Not really.")

Mitchell refused to comment on the current state of the band, saying only, "I don't think people realize how hard these kids work. One incident, and all the haters wanna start throwing rocks. It makes me wanna say, 'Go fuck yourself.'" If anything, what Talihina Sky highlights more than anything is the band's tenacity, their ability to transcend difficult circumstances and maintain a strange unity in the face of chaos. "One thing I hope comes out in the film is that these guys are a family first," Mitchell says, "They're going to keep that focus in place. And they’re gonna be back, and back better than ever."